So a RAM chip, a NAND module, and an “ultracapacitor” walk into stick...

This week Micron released a press blast for technology called, “NVDIMM”. The goal is to create memory modules which perform as quickly as DRAM but can persist without power. At this point you could probably guess the acronym: Nonvolatile Dual In-line Memory Module. It has been around for a few years now, but it is in the news now so let's chat about it.

I often like to play the game, “Was this named by an engineer or a marketer?” You can typically tell who was responsible for naming something by gauging how literally it breaks down into a simple meaning versus not having any apparent meaning at all. A good example of an engineer name is UHF, which breaks down into ultra-high frequency because it's higher than VHF, very-high frequency. A good example of a marketing name would be something like “Centrino”, which sounds like the biggest little penny-slot machine in the world. I would quite comfortable guessing that NVDIMM was named by an engineer.

This is AgigA Tech's module, who provides the capacitors for Micron and their NVDIMMs.

The actual makeup of NVDIMMs is quite sensible: DIMMs are fast but die when the power goes out. You could prevent the power from going out but it takes quite a lot of battery life to keep a computer online for extended periods of time. NAND Flash is quite slow, relative to DIMMs, in normal operation but can persist without power for very long periods of time. Also, modern-day capacitors are efficient and durable enough to keep DIMMs powered for long enough to be copied to flash memory.

As such, if the power goes out: memory is dumped to flash on the same chip. When power is restored, DIMMs get reloaded and continue on their merry way.

According to the Micron press release, the first NVDIMM was demonstrated last November at SC12. That module contained twice as much NAND as it did DIMM memory: 8GB of Flash for 4GB of RAM. Micron did not specify why they required having that much extra Flash memory although my gut instinct is to compensate for write wearing problems. A two-fold increase to offset NAND that had just one too many write operations seems like quite a lot compared to consumer drives. That said, SSDs do not have to weather half of their whole capacity being written to each time the computer shuts down.

Corsair's 256GB Performance Pro SSD is the member of the Performance series which utilizes Toshiba Toggle NAND and the Marvell 9174 controller. At $340 it is a little more expensive than some other comparable drives, however that may be well deserved for after their testing [H]ard|OCP put this drive in the same category as the Intel 520 in general performance. In fact during some tests they found it to be faster than the lauded Intel SSD, which is no mean feat. That performance, along with a solid three year warranty helped Corsair pick up a Silver Award from [H].

"Today we review the 256GB Corsair Performance Pro SSD. Corsair provides enthusiasts with both sides of the SSD controller coin by offering both Marvell and SandForce controlled SSDs in its product lines. Today we will take a look at the Marvell powered 256GB SSD and the Toshiba Toggle NAND that Corsair has chosen for it."